age = input()
age = int(age)
if age >= 80:
    print(">=80")
elif age >= 50:
    print(">=50")
else:
    print("<50")

i = 0
while i < 3:
    print(i)
    i += 1

name = "Sally"
for k in name:
    print(k)

for x in range(5):
    print(x)

for x in range(5, 10):
    print("x = %s" % x)

for x in range(5, 10, 2):
    print(f"x_c= {x}")

# python 中也有 continue break用法与C++相同

